Various forms of metal honeycomb substrates for catalytic converters have been proposed in the past. For example, the U.S. Pat. No. 4,559,205, issued on Dec. 17, 1985, entitled "Catalytic Converter Substrate and Retainer Assembly" and assigned to the assignee of this invention discloses a catalytic converter substrate of curved cross-sectional profile comprising a stack of modules individually formed of folded metal foil having contacting layers defining passages therebetween. The modules have a uniform thickness but various widths so as to conform the stack to the desired profile but with the combined thickness of the modules being made oversize such that the contacting layers are frictionally held together against relative sliding when the modules are compressively loaded by a retainer to completely conform to the desired profile.
Another patent which is assigned to the assignee of the present invention and shows a converter with a catalyst coated metal honeycomb substrate is U.S. Pat. No. 4,619,912 issued on Oct. 28, 1986, and entitled "Catalytic Converter Substrate." This patent discloses a metal substrate formed of two smooth foil strips and one corrugated foil strip arranged and folded together so that alternate folds of each of the smooth foil strips have spaced sides and juxtaposed abutting sides and interleave with those of the other smooth foil strips. This allows all of the folds, of the corrugated foil strips to have spaced sides that sandwich the folds with juxtaposed abutting sides of both the smooth foil strips so as to define passages therebetween. In addition, all of the strips are adapted to be retained together against telescoping by engaging retaining means at the opposite ends of all of their folds.
Yet another U.S. patent that has issued to the assignee of this invention and discloses a metal foil substrate catalytic converter is U.S. Pat. No. 5,187,142, issued on Feb. 16, 1993, in the name of Richmond et al. The catalytic converter seen in this patent has corrugated metal foil sheets secured together in a stack so that a plurality of axially extending fluid flow paths are defined therebetween. Disposed at predetermined intervals throughout the stack are foil retainer sheets having integral foil tabs extending outwardly from the side edges and folded about the outer side surface of the substrate to form a segmented foil skin thereabout. The segmented foil skin may be welded continuously along its length to secure the foil sheets in a unitary catalyst substrate and to provide a weld surface for attachment of the catalyst substrate directly to the converter canister wall.
Also, the U.S. Pat. No. 4,731,229 entitled "Reactor and Packing Element For Catalyzed Chemical Reactions", issued on Mar. 15, 1988, in the name of August Sperandio covers a reactor for performing heterogeneous catalyzed chemical reactions. The reactor comprises packing elements which are constructed of corrugated plates having inclined corrugations and catalyst members which are disposed between the plates. In one embodiment, the catalyst members have alternating fluted parts and unfluted parts with the fluted parts disposed within the troughs of the adjacent corrugated plate. In other embodiments, the catalyst members may be in the form of unfluted members, continuously fluted members and members which are disposed in planes between pairs of corrugated plates or within the troughs of the corrugated plates.
There is also U.S. Pat. No. 4,673,553 entitled "Metal Honeycomb Catalyst Support Having a Double Taper", issued on Jun. 16, 1987, in the name of William B. Retallick. This patent shows a catalytic converter that includes a metal honeycomb catalyst support anchored in a canister so that it cannot telescope or blow out of the canister. The honeycomb catalyst support is made by folding a strip of metal back and forth upon itself. The lines of folding are inclined to the perpendicular to the axis of the strip of metal. The repeating sequence of the inclinations is left, right, right, left, etc.. Folding the strip in this manner produces a honeycomb that has a taper in both of two directions so that it can be anchored in the canister.
The canister has a taper which coincides with the taper of the honeycomb.